In ancient India, Altrars with combination of shapes like rectangles, triangles and trapeziums were used for:

People primarily used alters and fireplaces to perform Vedic rites. In ancient India, the concept of geometry begins with the construction of these altars and fireplaces. They practise public worship as well as private worship.

Indian mathematics has played an important role since its inception, in Ancient India, and its primary function is to generate rules for systematic and accurate methods of calculation.

Sulbasutras, the oldest written mathematical score still available today.

Knowledge of applied mathematics 'geometrical figures' can be seen in Harappan civilization architecture even before this era.

The built altars with geometric shapes of squares and circles for private worship, while altars with a combination of geometric shapes of rectangles, triangles, and trapeziums were primarily used for public worship.